Interpretive Summary: This research was conducted to develop a more rapid and cost effective method to assess the genetic diversity of Phragmidium violaceum (blackberry rust). The genetic markers developed will help scientists to monitor genetic drift of introduced populations,discover isolates with potential to act as biological control agents of invasive blackberry, and look at factors influencing migration of the pathogen.

Technical Abstract:
Eleven polymorphic microsatellite markers were developed for the Uredinales fungus Phragmidium violaceum, which causes leaf rust on European blackberry (Rubus fruticosus L. aggregate). Allele frequency ranged between two and seventeen alleles per locus with no evidence of linkage disequilibrium among isolates from southern Australia (n=20) and the Pacific Northwest of the United States (n=27). These markers will be useful in studies investigating genetic diversity and evolution of P. violaceum in its introduced ranges in the United States and Australia.